This is because the wind strips away the thin layer of warm air above your skin. The stronger the wind, the more heat lost from your body, and the colder it will feel. When the winds are light, it will feel closer to the actual air temperature.

Wind Chill Chart

The blue-shaded areas represent the amount of time it takes to get frostbite at the corresponding wind chill temperatures.

You can determine your wind chill temperature using the chart above. Find the value closest to the outside air temperature, then the value that is closest to the current wind speed. Your wind chill temperature is the value where the lines drawn from the air temperature and the wind intersect.

The blue-shaded areas in the wind chill chart represent the amount of time it takes to get frostbite at the corresponding wind chill temperatures.

For example, with an air temperature of minus 20 degrees and a wind speed of 15 mph, frostbite can occur in 10 minutes or less.

If you live alone, ask a family member or neighbor to check on you daily

If your body temperature is 96 degrees or less, you feel cold and sluggish, or are having trouble thinking clearly, the NWS says to see your doctor immediately or go to the nearest emergency room. "It's better to be overly cautious than to die of a disorder that does not have to be deadly."

Frostbite

Frostbite occurs when body tissue freezes, such as your fingers, toes, ear lobes or the tip of your nose. In order to protect vital organs, your body cuts circulation to your extremities, including your feet, hands and nose, which eventually freeze.

New Zealand climber Mark Inglis, a double amputee, shows his badly frostbitten fingers as he arrives at Auckland International airport after returning from Kathmandu, Nepal, on May 25, 2006, in Auckland, New Zealand.

(Sandra Mu/Getty Images)

In order to avoid frostbite, the best thing to do is stay inside when it is bitterly cold. If you have to be outside, you should cover every part of your body, including your ears, nose, toes and fingers. You also want to keep your skin dry and stay out of the wind when possible.

#20: Boston (Avg. Dec-Feb Temp: 31.8 degrees)

Boston's all-time record low was -18 degrees set on Feb. 9, 1934. Once every 1-2 years the city shivers in subzero cold. Subfreezing temperatures occur 94 days a year, there. (Photo: Darren McCollester/Getty Images)

The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.